Final answer:
The term that means the site where the nerves and blood vessels enter and leave an organ is the hilum.
Step-by-step explanation:
The term that means the site where the nerves and blood vessels enter and leave an organ is the hilum. The hilum is the concave part of an organ where these structures enter or exit. For example, in the kidney, the hilum is the entry and exit site for vessels, nerves, lymphatics, and ureters.